1. Field of the Invention
The invention relates to a scintillator panel. Further, the invention relates to a scintillator panel for a radiation detecting apparatus which is used for a medical diagnosing apparatus, a non-destructive inspecting apparatus, or the like and, more particularly, to a scintillator panel for a radiation detecting apparatus which is used for X-ray photographing or the like. In the specification, explanation will be made on the assumption that electromagnetic waves such as X-ray, α-ray, β-ray, γ-ray, and the like are also included in the radiation.
2. Related Background Art
Hitherto, an X-ray film system having a fluorescent screen having an X-ray phosphor therein and a duplicated sensitive agent has generally been used for photographing an X-ray picture. However, in recent years, a digital radiation detecting apparatus having an X-ray phosphor layer and a 2-dimensional photodetector has advantages that image characteristics are excellent and, since data is digital data, by fetching the data into a computer system connected to a network, the data can be shared. Therefore, research and development have vigorously been made with respect to the digital radiation detecting apparatus and various patent applications have also been filed.
As a digital radiation detecting apparatus, a scintillator panel for a radiation detecting apparatus constructed in such a manner that a reflective layer and a protective layer of a thin metal film are formed on a supporting substrate which transmits a radiation and, further, a phosphor layer is formed on the protective layer has been disclosed in U.S. Pat. No. 2002/0017613 A1. By providing the protective layer between the phosphor layer and the reflective layer in the scintillator panel, it is prevented that a function as a reflective film of the reflective layer is attenuated due to alteration or the like by components and moisture contained in the phosphor layer.
A columnar (needle) crystal of alkali halide is used as a scintillator material used in the above prior art. Further, a few % metal such as Tb, Eu, or the like is uniformly contained into alkali halide as a light emission activator. A vacuum evaporation depositing method is used for forming the columnar crystal. In order to simultaneously evaporation-deposit alkali halide and the light emission activator and, further, make the most of an effect of the light emission activator, the columnar crystal is left in an atmosphere of 200 to 260° C.
Examples of a scintillator panel disclosed in U.S. Pat. No. 2002/0162965 AA are shown in FIGS. 7, 8A, and 8B. Only an insulative layer 215 is formed on a supporting substrate 211 (FIG. 7) or the insulative layer 215 is formed thereon and a metal reflective layer 214 is formed on the insulative layer 215 (FIG. 8B).
In a scintillator panel 210 for the radiation detecting apparatus disclosed in the prior art mentioned above, a conductive substrate such as amorphous carbon substrate, metal substrate like an aluminum substrate, or the like is used as a supporting substrate 211. Particularly, the reasons why the amorphous carbon substrate is used as a supporting substrate 211 are as follows.
1. Since an absorption amount of X-ray of the amorphous carbon substrate is smaller than that of a glass substrate or an aluminum substrate, a larger amount of X-ray can be transmitted into the phosphor layer. 2. Chemical resistance is excellent. 3. Heat resistance is excellent.